Strategic thinking suggests that they should take the country one State at a time. Then they should consolidate their forces and move on to the next State. Arizona might be among the first States to be taken. Arizona is a free-thinking State in many ways. And she has a lot of open, unused countryside. Taking her would be a good start for demoralizing the rest of the country. Besides, re-routing the Colorado River would make all of LA collapse, thereby starting the California take-over with a bang.